In February Waymo filed a lawsuit claiming that a former manager took technical data when he left to launch a competing venture that was later acquired by Uber.

Most major automakers and several other technology firms have been stepping up efforts on autonomous driving in recent years, contending these systems will eliminate the vast majority of road accidents. Apple is the latest to have obtained a testing permit in California.

German luxury carmaker Daimler and auto parts supplier Bosch announced plans this month to work together to create completely driverless cars in the next few years.

US-based Tesla is also stepping up efforts, as are several Chinese technology firms and the major US, Asian and European manufacturers.